1. Field of the Invention
The invention relates to a semiconductor structure, and in particular to a thin film transistor array substrate structure and fabrication method thereof.
2. Description of the Related Art
Liquid crystal displays (LCDs) are popularly utilized in personal computers, word processors, navigation systems, amusement machines, projectors, viewfinders and portable machines (such as watches, electronic calculators and televisions) because of low power consumption, thin profile, light weight and low driving voltage.
A color filter (CF) is a key component of a color LCD. Typically, the color filter and thin film transistors (TFTs), which act as driving switches, are disposed on two separate substrates and located on the opposite side of the liquid crystal layer. To prevent light from damaging the TFTs, a black matrix is formed on the color filter's substrate, above the thin film transistors. This arrangement, however, increases costs, processing time, and manufacturing complexity. Additionally, the black matrix must be wider in consideration of alignment errors, thus reducing panel aperture ratio.
In order to increase the panel aperture ratio, a color filter on array (COA) technique has been developed. The conventional COA method, however, requires 9 processes including 5 array processes and 4 color filter processes, increasing costs.